We've heard a great deal of rumors about the next-generation Mitsubishi EVO going hybrid, but now it appears Subaru is planning a more fuel efficient version of the WRX STI – thanks to the use of a diesel engine. That's right, according to a report by AutoCar, the next-gen STI (likely due in 2012) will get a pumped-up version of the 2.0-liter turbodiesel motor offered in the current Impreza overseas.

Regardless, we're not likely to see any such model in North America. High-performance diesels are, however, not unheard of in Europe with Volkswagen even offering a diesel power golf based on the GTI: called the GTD. We just hope Subaru doesn't follow suit with the naming… STD?

A gasoline-powered STI will continue on as well, although AutoCar suggests a tiny 1.5-liter 4-cylinder might be used to power it. That is also unlikely in North America where the current STI gets a 2.5-liter engine – already an increase over the 2.0-liter used overseas.

In addition, the Japanese automaker is reportedly working on a hybrid setup for the car, but its not likely to arrive until at least 2015.